C. Palet et al., SELECTIVE-MEMBRANE TRANSPORT OF DICARBOXYLIC-ACIDS IN THEIR NEUTRAL FORM BY A SYNTHETIC RECEPTOR-CONTAINING AMIDOPYRIDINE GROUPS, Analytica chimica acta, 343(3), 1997, pp. 287-294
A synthetic receptor that can discriminate dicarboxylic acids based on
host-guest principles has been prepared. This compound incorporates t
wo amidopyridine units as hydrogen-bonding centers that are capable of
binding the carboxylic acid functional group. The receptor was dissol
ved in a kerosene/dodecanol mixture and used as a carrier in supported
liquid membranes. Facilitated transport based on the liquid-liquid di
stribution of dicarboxylic acids between aqueous feed and stripping so
lutions and an organic phase containing the carrier was accomplished.
This transport was driven by a pH gradient that assures the predominan
ce of the protonated neutral form of the carboxylic acids in the feed
solution and the corresponding deprotonated form in the stripping solu
tion. Selective transport of dicarboxylic acids was observed allowing
for an efficient separation of different carboxylic acids.